It's definitely a matter of taste, and it's fine that different folks prefer different stuff. The flat model works well enough for Metafilter -- we're constant

It's definitely a matter of taste, and it's fine that different folks prefer different stuff. The flat model works well enough for Metafilter -- we're constantly seeing thoughtful, responsive conversations on all kinds of topics in the site's discussion threads -- but it's a virtue of the web that there's a variety of models out there so different folks can have their preferences met.